some filesystem command signatures (#7464)

# Description

Signature for the following commands:

- `cd` 
- `cp` 
- `glob` 
- `ls` 
- `mkdir` 
- `mv` 
- `open`
- `rm`
- `save`
- `touch`

Related to https://github.com/nushell/nushell/issues/7320

Co-authored-by: sholderbach <sholderbach@users.noreply.github.com>

crates/nu-command/src/filesystem/cd.rs

@@ -48,6 +48,7 @@ impl Command for Cd {
 
     fn signature(&self) -> nu_protocol::Signature {
         Signature::build("cd")
+            .input_output_types(vec![(Type::Nothing, Type::Nothing)])
             .optional("path", SyntaxShape::Directory, "the path to change to")
             .input_output_types(vec![
                 (Type::Nothing, Type::Nothing),

crates/nu-command/src/filesystem/cp.rs

@@ -8,7 +8,7 @@ use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
     Category, Example, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature, Span,
-    Spanned, SyntaxShape, Value,
+    Spanned, SyntaxShape, Type, Value,
 };
 
 use super::util::try_interaction;
@@ -40,6 +40,7 @@ impl Command for Cp {
 
     fn signature(&self) -> Signature {
         Signature::build("cp")
+            .input_output_types(vec![(Type::Nothing, Type::Nothing)])
             .required("source", SyntaxShape::GlobPattern, "the place to copy from")
             .required("destination", SyntaxShape::Filepath, "the place to copy to")
             .switch(

crates/nu-command/src/filesystem/glob.rs

@@ -4,7 +4,7 @@ use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
     Category, Example, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature, Spanned,
-    SyntaxShape, Value,
+    SyntaxShape, Type, Value,
 };
 use wax::{Glob as WaxGlob, WalkBehavior};
 
@@ -18,6 +18,7 @@ impl Command for Glob {
 
     fn signature(&self) -> Signature {
         Signature::build("glob")
+            .input_output_types(vec![(Type::Nothing, Type::List(Box::new(Type::String)))])
             .required("glob", SyntaxShape::String, "the glob expression")
             .named(
                 "depth",

crates/nu-command/src/filesystem/ls.rs

@@ -9,7 +9,7 @@ use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
     Category, DataSource, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
-    PipelineMetadata, ShellError, Signature, Span, Spanned, SyntaxShape, Value,
+    PipelineMetadata, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
 };
 use pathdiff::diff_paths;
 
@@ -37,6 +37,7 @@ impl Command for Ls {
 
     fn signature(&self) -> nu_protocol::Signature {
         Signature::build("ls")
+            .input_output_types(vec![(Type::Nothing, Type::Table(vec![]))])
             // Using a string instead of a glob pattern shape so it won't auto-expand
             .optional("pattern", SyntaxShape::String, "the glob pattern to use")
             .switch("all", "Show hidden files", Some('a'))

crates/nu-command/src/filesystem/mkdir.rs

@@ -6,7 +6,7 @@ use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
     Category, Example, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature,
-    SyntaxShape, Value,
+    SyntaxShape, Type, Value,
 };
 
 #[derive(Clone)]
@@ -19,6 +19,7 @@ impl Command for Mkdir {
 
     fn signature(&self) -> Signature {
         Signature::build("mkdir")
+            .input_output_types(vec![(Type::Nothing, Type::List(Box::new(Type::String)))])
             .rest(
                 "rest",
                 SyntaxShape::Directory,

crates/nu-command/src/filesystem/mv.rs

@@ -7,7 +7,7 @@ use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
     Category, Example, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature, Span,
-    Spanned, SyntaxShape, Value,
+    Spanned, SyntaxShape, Type, Value,
 };
 
 const GLOB_PARAMS: nu_glob::MatchOptions = nu_glob::MatchOptions {
@@ -35,6 +35,7 @@ impl Command for Mv {
 
     fn signature(&self) -> nu_protocol::Signature {
         Signature::build("mv")
+            .input_output_types(vec![(Type::Nothing, Type::List(Box::new(Type::String)))])
             .required(
                 "source",
                 SyntaxShape::GlobPattern,

crates/nu-command/src/filesystem/open.rs

@@ -3,7 +3,8 @@ use nu_engine::{eval_block, CallExt};
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
-    Category, Example, PipelineData, RawStream, ShellError, Signature, Spanned, SyntaxShape, Value,
+    Category, Example, PipelineData, RawStream, ShellError, Signature, Spanned, SyntaxShape, Type,
+    Value,
 };
 use std::io::BufReader;
 
@@ -35,6 +36,7 @@ impl Command for Open {
 
     fn signature(&self) -> nu_protocol::Signature {
         Signature::build("open")
+            .input_output_types(vec![(Type::Nothing, Type::Any), (Type::String, Type::Any)])
             .optional("filename", SyntaxShape::Filepath, "the filename to use")
             .switch("raw", "open file as raw binary", Some('r'))
             .category(Category::FileSystem)

crates/nu-command/src/filesystem/rm.rs

@@ -44,7 +44,13 @@ impl Command for Rm {
     }
 
     fn signature(&self) -> Signature {
-        let sig = Signature::build("rm");
+        let sig = Signature::build("rm")
+            .input_output_types(vec![(Type::Nothing, Type::List(Box::new(Type::String)))])
+            .required(
+                "filename",
+                SyntaxShape::Filepath,
+                "the path of the file you want to remove",
+            );
         #[cfg(all(
             feature = "trash-support",
             not(target_os = "android"),
@@ -73,7 +79,7 @@ impl Command for Rm {
             .rest(
                 "rest",
                 SyntaxShape::GlobPattern,
-                "the file path(s) to remove",
+                "additional file path(s) to remove",
             )
             .category(Category::FileSystem)
     }

crates/nu-command/src/filesystem/save.rs

@@ -2,7 +2,8 @@ use nu_engine::CallExt;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
-    Category, Example, PipelineData, RawStream, ShellError, Signature, Spanned, SyntaxShape, Value,
+    Category, Example, PipelineData, RawStream, ShellError, Signature, Spanned, SyntaxShape, Type,
+    Value,
 };
 use std::fs::File;
 use std::io::{BufWriter, Write};
@@ -35,6 +36,7 @@ impl Command for Save {
 
     fn signature(&self) -> nu_protocol::Signature {
         Signature::build("save")
+            .input_output_types(vec![(Type::Any, Type::Nothing)])
             .required("filename", SyntaxShape::Filepath, "the filename to use")
             .named(
                 "stderr",

crates/nu-command/src/filesystem/touch.rs

@@ -7,7 +7,9 @@ use filetime::FileTime;
 use nu_engine::CallExt;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{Category, Example, PipelineData, ShellError, Signature, Spanned, SyntaxShape};
+use nu_protocol::{
+    Category, Example, PipelineData, ShellError, Signature, Spanned, SyntaxShape, Type,
+};
 
 #[derive(Clone)]
 pub struct Touch;
@@ -23,6 +25,7 @@ impl Command for Touch {
 
     fn signature(&self) -> Signature {
         Signature::build("touch")
+            .input_output_types(vec![ (Type::Nothing, Type::Nothing) ])
             .required(
                 "filename",
                 SyntaxShape::Filepath,